Three-dimensional assemblies built up by quantum dots in size-quantization regime: Band gap shifts due to size-distribution of cadmium selenide nanoparticles

• Optical absorption of 3D QD assemblies in size-quantization regime is modeled.
• Band gap energy of the QD solid depends on the size-distribution of the nanoparticles.
• QD solid samples with same 〈R〉 exhibit band gap shift depending on size distribution.
• QD size distribution leads to large Urbach energies.

In the present study, it is predicted that the band gap energy of a three-dimensional quantum dot assembly exhibits a red shift when the dispersion of the crystal size distribution is enlarged, even at a fixed average value thereof. The effect is manifested when the size quantization regime in individual quantum dots constituting the assembly has been entered. Under the same conditions, the sub-band gap absorption tails are characterized with large Urbach energies, which could be one or two orders of magnitude larger than the value characteristic for the non-quantized case.

Band gap shifts due to size-distribution of nanoparticles in 3D assemblies built up by quantum dots in size-quantization regime.Figure optionsDownload as PowerPoint slide